Determining which wires to splice

Yes, my electrical skills are sorely lacking.

The cats or more likely dog chewed through the cord on the dustbuster charger. The cord consists of two insulated stranded copper wires, and I want to solder it back together. Unfortunately, it was too damaged to determine which wire matches the other, and they aren’t color coded. Any way I can do this with a multimeter? Does it even matter which one goes to where?

It is standard US power, and output is 18V AC 300 mA.

If it were me…
Plug it in.
Ground one side of your multimeter and then test the two wires coming from the transformer. Figure out which one is hot.

Now, switch your multimeter to check for continuity. Put one terminal inside the the barrel (the part the plugs into the the dustbuster). Figure out which wire that correlates with.

Attach the hot wire to the wire that goes to the inside of the barrel connector. Attache the other two wires.

See what happens.

Actually, before you even start, look at the transformer. It should have a little diagram with a Plus on one side and a minus on the other. That diagram will show you which part of the barrel is supposed to be hot. I’m assuming the inside is. In the unlikely scenario where the outside of the barrel is hot, just hook the wires together the opposite way.

Since the output is AC, it doesn’t matter which wire goes where.

On many cables, rather than color coding, there is a ridge on one side of the cord, to mark one of the wires.

But as beowulff said, it doesn’t matter for AC.

Thanks all! I felt that it didn’t matter, but didn’t have a good explanation why; that makes sense.

Joey P, it’s a loading dock type charger, no barrel. But what you said can probably be transferred to the two contact plates on it.